Conventionally, as a display device usable for a display of a mobile terminal, a TV or the like, an organic EL (electroluminescence) display device including an organic EL element is known. An organic EL display device has advantages of emitting bright light, having superb viewing angle characteristics, and the like, and thus rapid development thereof is desired to provide a display device replacing a liquid crystal display device.
Organic EL materials usable for the light emitting element include a low molecular weight-type organic EL material and a high molecular weight-type organic EL material. In the case where a low molecular weight-type organic EL material is used, a film is usually formed by vapor deposition by use of a blocking mask. In this case, a blocking mask is located between a substrate including pixel electrodes and a vapor source, and vapor deposition is performed in the state where a plurality of openings provided in the blocking mask are positionally matched to the pixel electrodes. As a result, a thin film of an organic EL material is formed selectively on desired pixel electrodes (Japanese Laid-Open Patent Publication No. 2002-231449).